I'm having the same issue for conection with every mod versión, signed & unsigned. I've tried them in BlueStacks emulador (rooted) and even the original game Is not working at least for Android 7 Nougat (this version haven't security updates support anymore), so I think this happens because the Devs of this game are already working to update all their products to android 10 security systems which would probably be mandatory for all Google games in October 21.
In conclusion: I think we should wait for the almighty modders to "mod my love" even with the newer security systems (and hope that It could be "signed") for the sake of my pocket.